Bar and wire rod rolling mill headless rolling has high production efficiency, improves the material yield by reducing the cutting loss of the cutting head, overcomes the dimensional deviation of the tail of the rolling stock to improve the dimensional accuracy, and reduces the head and tail of the rolling stock to the motor, transmission system, roll, and guide. A series of obvious advantages, such as impact and reduction of accidents, are highly praised and studied by rolling mill workers.
At present, there are two types of bar and wire rod rolling mill headless rolling technology:
1. EWR endless rolling technology is to cut the slab and then heat it. After the furnace is finished, or after the roughing unit, the two slabs (rolled parts) are welded together end to end to achieve endless rolling. This technology for headless rolling by welding is called EWR, which was developed by Japanese manufacturers and applied first.
EWR headless rolling technology cuts the original blank without head and tail and then welds it into a headless and tailless workpiece. This is really to solve the problem of the mismatch between the speed of the continuous casting machine and the rolling mill.
This process, while enjoying the many benefits of headless rolling, also presents a series of thorny issues. First and foremost, the welding equipment is complicated, the number of accidents increases, and the operating rate is affected at the initial stage of commissioning. After short-term trials, Tangshan Iron and Steel Co., Ltd. abandoned the efforts to further improve this technology and restored the original single rolling operation mode, which affected other manufacturers' views on the EWR headless rolling process. The person is discouraged.
2. Luna headless rolling process is developed by Italy Danieli company, has been applied to Luna headless rolling in Udine, Italy, which is characterized by the direct connection of billet continuous casting machine and continuous rolling mill on a production line, the slab is not cut, and after the tunnel furnace induction heat is applied, direct rolling is realized. After rolling, it is cut into a fixed-length for cooling and subsequent treatment.
Compared with the EWR rolling process, Luna's headless rolling process avoids cutting off the re-welding, welding, and re-cutting. It is a major technological innovation in the field of rod and wire production and represents the future development direction of bar and wire rod rolling mill production technology. However, the disadvantage of the Luna process is that it still needs to use a long tunnel furnace for induction heating, which has high construction cost and running cost.
In general, bar and wire rod rolling mill headless rolling technology still have the need for further research.